The present invention relates to fluorochemical compositions for the treatment of substrates, in particular fibrous substrates such as textiles to impart stain release properties to those substrates.
Fluorochemical compositions for the treatment of substrates such as leather, textiles and paper, are well known and are used to impart various properties to the substrate such as water and/or oil repellency, waterproofness, anti-staining, and soil-resistance. For example, U.S. Pat. No. 5,100,954 discloses a soil resisting agent containing, as an effective component, a copolymer of (I) a fluorine-containing urethane compound containing a (meth)acryloyl group or an allyl group, and a polyfluoroalkyl group, obtained by reacting (a) a polyfunctional isocyanate having at least trifunctionality, (b) a hydroxy compound containing a (meth)acryloyl group or an allyl group, and (c) a hydroxy compound having a polyfluoroalkyl group, and (II) a copolymerizable compound other than said fluorine-containing urethane compound.
U.S. Pat. No. 4,920,190 describes certain fluorochemical compositions that are based on polymers of fluorinated acrylic monomers in which a perfluoroalkyl group is linked by 2,4-toluenediisocyanate to an acrylate or methacrylate. Amongst useful acrylates and methacrylates are mentioned mono-(meth)acrylates of polyalkyleneglycols. The fluorochemical compositions are said to be suitable as water or oil-repellents for various substrates and in particular leather. U.S. Pat. No. 4,778,915 describes certain polymers of fluorinated acrylic monomers that contain a perfluoroalkyl group linked to an acrylate or methacrylate by a di-isocyanate, for use as water or oil repellents.
Fluorochemical compositions are also used to facilitate stain or soil release from a substrate such as, for example, a fabric. Routine treatments of fabrics with various modifying additives such as softeners, stiffeners, and lubricants, to impart desired properties to a commercial fabric typically increase the oleophilicity of the fabric, thereby significantly increasing its tendency to accept oily stains and reducing its ability to release such stains after laundering. Fluorochemical compositions based on a mixture of a fluorinated compound and a non-fluorinated hydrophilic compound or a chemical xe2x80x9chybridxe2x80x9d compound containing fluorochemical oleophobic segments (xe2x80x9cFxe2x80x9d) and non-fluorinated hydrophilic segments (xe2x80x9cHxe2x80x9d) are known to act as stain release compositions since they provide oil repellency during normal wear and inhibit wicking or diffusion of oily soils into the fabric or fiber bundles as well as facilitate soil release during laundering.
For example, U.S. Pat. No. 4,859,754 describes certain water and oil repellent treatments having desoiling properties that are composed of a polyfluorinated group containing copolymer obtained by copolymerizing a first and second monomer wherein the first monomer contains a polyfluorinated group and the second monomer is an amphiphatic monomer having a hydrophilic moiety and a lipophilic moiety.
U.S. Pat. No. 3,920,614 describes certain high soil release oil-and water repellent copolymers prepared by copolymerization of at least 25% by weight of a fluoroalkyl monomer and 5 to 50% by weight of poly(oxyethylene) acrylate or methacrylate.
U.S. Pat. No. 4,695,488 describes certain polymers obtained by homopolymerization of poly(oxyalkylene) monomers terminated by fluorinated groups. According to the disclosure, a composition based on this polymer could impart stainproofing properties with good durability to a substrate such as plastics, fabric and paper.
Despite the many fluorochemical compositions known to impart stain release properties to a substrate, there continues to be a desire for fluorochemical compositions with improved properties. Desirable properties include easy cleanability of substrates based on natural fibers such as cotton and blends of cotton and polyester, particularly with respect to oil type stains (dirty motor oil, vegetable oil) and water based stains (tea, coffee, wine); low manufacturing cost; high storage stability; easy emulsifiability and high performance even if applied in low quantities. It is also desired that the fluorochemical compositions provide good stain release properties and oil and/or water repellency properties to the substrate.
The present invention provides a method of treatment of a substrate comprising the step of contacting said substrate with a fluorochemical composition comprising a polymer derived from polymerization of monomer corresponding to the following general formula (I): 
wherein:
Rf is selected from the group consisting of perfluorinated or partially fluorinated aliphatic groups;
L1 and L2 are each independently an organic divalent linking group and they may be the same or different;
L3 represents an organic linking group with a valence of n+1;
t is 0 or 1;
n is an integer of 2 to 20;
A1 and A2 are each independently selected from the group consisting of divalent residues obtained by removing 2 xe2x80x94NCO groups from a corresponding diisocyanate;
X1 is selected from the group consisting of O, NH and S;
X2 is selected from the group consisting of O, NH and S;
B1 represents a hydrophilic residue obtained by removing the groups HX1 and HX2 from a compound HX1xe2x80x94B1xe2x80x94X2H that comprises a poly(oxyalkylene) group;
G represents a free radical polymerizable group; and
s is 0 or 1 with the proviso that when s is 0, L2 represents a hydrophilic segment comprising a poly(oxyalkylene) group or said polymer is derived from a copolymerization of a monomer according to formula (I) and a poly(oxyalkylene) group containing monomer.
Also provided is a fluorochemical composition comprising a polymer derived from a polymerization of a monomer corresponding to the following general formula (I): 
wherein:
Rf is selected from the group consisting of perfluorinated or partially fluorinated aliphatic groups;
L1 and L2 are each independently selected from the group consisting of organic divalent linking groups;
L3 is an organic linking group with a valence of n+1;
t is 0 or 1;
n is an integer of 2 to 20;
A1 and A2 are each independently selected from the group consisting of divalent residues obtained by removing twp xe2x80x94NCO groups from a corresponding diisocyanate;
X1 is selected from the group consisting of O, NH and S;
X2 is selected from the group consisting of O, NH and S;
B1 represents a hydrophilic segment comprising a poly(oxyalkylene) group;
G represents a free radical polymerizable group; and
s is 0 or 1 with the proviso that when s is 0, L2 represents a hydrophilic segment comprising a poly(oxyalkylene) group or said polymer is derived from a copolymerization of a monomer according to formula (I) and a poly(oxyalkylene) group containing monomer.
There is further provided a use of the fluorochemical composition to provide good stain release properties to a substrate and a substrate comprising on at least one of its surfaces, the fluorochemical composition.
Further provided are a monomer according to formula (I) above and a monomer composition including a monomer according to formula (I) and a poly(oxyalkylene)-containing monomer.
The polymer used in the fluorochemical composition is derived from at least one monomer according to formula (I) above. If the monomer according to formula (I) includes a poly(oxyalkylene) group, i.e. s is 1, and/or L2 contains a polyoxyalkylene a homopolymer of the monomer of formula (I) can be used as well as a copolymer of that monomer. The polyoxyalkylene group is typically of a sufficient length such that sufficient wetting of the substrates occurs during laundering thereby facilitating removal of stain. Preferably, the number of oxyalkylene moieties in the poly(oxyalkylene) group is between about 18 and 275 or between about 20 and 190 and more preferably between about 23 and 95. In case the monomer according to formula (I) does not include the poly(oxyalkylene) group, the polymer is derived from at least a monomer of formula (I) and at least one comonomer that includes a poly(oxyalkylene) group preferably having between about 5 and 16 oxyalkylene moieties.
The polymer may further include other ethylenically unsaturated comonomers such as vinylacetate, acrylates and methacrylates (e.g., methyl(meth)acrylate, glycidyl methacrylate, ethyl(meth)acrylate), vinylchloride, vinylidenechlorides, styrenes, acrylic acids, methacrylic acids and acrylonitriles. Other suitable comonomers include urethane-acrylate or urethane-methacrylate type monomers that can be obtained by the reaction of a diisocyanate and a hydroxy or amino-functionalised acrylate or methacrylate and another hydroxy or amino-functionalised compound such as an isocyanate blocking agent. Particular examples of the latter type of comonomers include the reaction product of a disocyanate, 2-hydroxyethyl(meth)acrylate and 2-butanone oxime or the reaction product of a diisocyanate, a mono (meth)acrylate of a polyethylene glycol and 2-butanone oxime.
Typically, the polymer includes between about 25% and 100% based on the total number of units in the polymer, preferably between about 40% and 100% of units derived from a monomer according to formula (I) that contains a poly(oxyalkylene) group.
In case the polymer is derived from monomers according to formula (I) that do not include the poly(oxyalkylene) group, the polymer also includes a comonomer that contains poly(oxyalkylene) groups. In this instance, the number of moieties in the polymer derived from monomers according to formula (I) not including poly(oxyalkylene) is preferably between about 5% and 50%, more preferably between about 15% and 40% and the number of units derived from a poly(oxyalkylene) containing comonomer is preferably between about 50% and 95% and more preferably between about 60% and 85%.
The fluorinated aliphatic group, Rf, is preferably a fluorinated, stable, inert, preferably saturated, non-polar, monovalent alkyl group. It can be straight chain, branched chain, or cyclic or combinations thereof It can contain heteroatoms, bonded only to carbon atoms, such as oxygen, divalent or hexavalent sulfur, or nitrogen. Rf is preferably a fully-fluorinated alkyl group, but hydrogen or chlorine atoms can be present as substituents, but preferably not more than one atom of either is present for every two carbon atoms. The Rf group typically has at least about 3 carbon atoms, preferably about 3 to 14 carbon atoms and more preferably at least about 6 carbon atoms. Rf preferably contains about 40% to 80% fluorine by weight, more preferably about 50% to 78% fluorine by weight. The terminal portion of the Rf radical is preferably a perfluorinated moiety, preferably containing at least about 7 fluorine atoms, e.g., CF3CF2CF2xe2x80x94, (CF3)2CFxe2x80x94, F5SCF2xe2x80x94. Preferred Rf groups are fully or substantially fluorinated and are preferably those perfluorinated alkyls according to the formula CmF2m+1xe2x80x94where m is 3 to 14. A monomer according to formula (I) includes a plurality of Rf groups as indicated by the variable n. Preferably, the monomer contains 3 to 6 or more Rf groups. Most preferably, the number of Rf groups in the monomer is between about 4 and 9.
Preferably, t in formula (I) represents 1 and an organic divalent linking group L1 is present. Linking groups L1 include straight chain, branched chain or cyclic alkylene, arylene, aralkylene, oxy, oxo, thio, sulfonyl, sulfoxy, amino, imino, sulfonamido, carbonamido, carbonyloxy, urethanylene, ureylene groups, and combinations thereof such as sulfonamidoalkylene or carbonamidoalkylene. A particularly preferred linking group L1 is represented by one of the following formulas: 
wherein:
R3 is selected from the group consisting of linear or branched alkylenes having 2 to 4 carbon atoms, and
R4 represents an alkyl having about 1 to 4 carbon atoms, for example methyl, ethyl or n-butyl.
L3 is a linking group with a valence of n+1 that preferably corresponds to the following formula: 
xe2x80x83wherein:
xe2x80x83n is as defined above,
Z represents the residue of a free radical initiator,
R5 is hydrogen or a methyl group,
X5 is S,
X6is O or NH and
L5 represents an alkylene preferably having 2 to 4 carbon atoms.
B1 is the hydrophilic residue obtained by removing the groups HX1 and HX2 from a compound HX1xe2x80x94B1xe2x80x94X2H that comprises a poly(oxyalkylene) group. Suitable poly(oxyalkylene)groups include those of which the oxyalkylene moiety has 2 to 4 carbons such as xe2x80x94OCH2xe2x80x94CH2xe2x80x94, xe2x80x94OCH2xe2x80x94CH2xe2x80x94CH2xe2x80x94, xe2x80x94OCH(CH3)CH2xe2x80x94, and xe2x80x94OCH(CH3)CH(CH3)xe2x80x94. The oxyalkylene moieties in the poly(oxyalkylene) group can be the same, as in poly(oxypropylene), or can be present as a mixture, as in a heteric straight or branched chain polymer or polymer with randomly distributed oxyethylene and oxypropylene moieties, or as in a straight or branched chain polymer with blocks of oxyethylene units and blocks of oxypropylene units. The poly(oxyalkylene) chain can be interrupted by or include one or more catenary linkages. Where the catenary linkages have three or more valences, they provide a means for obtaining a branched chain of oxyalkylene moieties. The poly(oxyalkylene) group may further contain a mixture of oxyalkylene moieties such as a mixture of oxyethylene and oxypropylene. Preferably, the majority of oxyalkylene moieties are oxyethylene, and preferably the number of oxyethylene moieties is at least about 50% and more preferably at least about 70%. The average number of oxyalkylene moieties is typically between about 18 and 275 and more preferably between about 25 and 182. B1 may also include an organic divalent linking group that links the poly(oxyalkylene) group to X1 or X2. Such organic divalent linking group is preferably a lower alkylene moiety having between 1 and 4 carbon atoms such as a methylene or ethylene moiety. Preferably, B1 is the hydrophilic residue obtained by removing the groups HX1 and HX2 from a compound HX1xe2x80x94B1xe2x80x94X2H selected from the group consisting of poly(oxyalkylene)diols (such as polyethyleneglycol), poly(oxyalkylene)thiols and poly(oxyalkylene)diamines.
L2 is an organic divalent linking group such as oxy, amino, linear or branched alkylenes having 1 to 4 carbon atoms or poly(oxyalkylenes) containing a group such as polyethyleneoxide or polypropyleneoxide. In the case where s is 0, L2 preferably comprises a poly(oxyalkylene) group having between about 5 and 20 oxyalkylene groups.
G is a free radical polymerisable group and is typically an ethylenically unsaturated group. Particularly preferred is an xcex1,xcex2-ethylenically unsaturated carbonyl group such as xe2x80x94COxe2x80x94CHxe2x95x90CH2 and xe2x80x94COxe2x80x94C(CH3)xe2x95x90CH2. Accordingly, in a preferred embodiment, L2xe2x80x94G together represent a moiety corresponding to the following formula (II): 
xe2x80x83wherein:
X3 and X4 each independently are selected from O or NH,
R1 is a linear or branched alkylene having 2 to 4 carbon atoms or a poly(oxyalkylene) containing group, and
R2 is hydrogen or a methyl group.
The monomers according to formula (I) wherein s is 1 are typically prepared according to the following general procedure. In a first reaction, an oligomer containing a plurality of Rf groups and a functionality capable of reacting with an isocyanate is reacted with a diisocyanate. The oligomers can be prepared according to the procedure described in, e.g., U.S. Pat. No. 5,292,796. Typically, their preparation involves a free radical polymerisation of a fluorochemical compound having an ethylenic unsaturation in the presence of an end-capping agent that includes a functional group capable of reacting with an isocyanate. Fluorochemical compounds having an ethylenic unsaturation are disclosed, e.g., in U.S. Pat. No. 2,803,615 (Ahlbrecht et al.) and U.S. Pat. No. 2,841,573 (Ahlbrecht et al.). Examples of such compounds include general classes of fluorochemical olefins such as acrylates, methacrylates, vinyl ethers, and allyl compounds containing fluorinated sulfonamido groups, acrylates or methacrylates derived from fluorochemical telomer alcohols, fluorochemical thiols, and the like. Preferred compounds include N-methyl perfluorooctanesulfonamidoethyl acrylate, N-methylperfluorooctanesulfonamidoethyl methacrylate, N-ethylperfluorooctanesulfonamidoethyl acrylate, N-methylperfluorohexylsulfonamidoethyl acrylate, perfluorooctyl acrylate, N-methyl perfluorooctanesulfonamidoethylvinyl ether, and C8F17SO2NHCH2 CHxe2x95x90CH2, 2-perfluoroalkyl ethyl(meth)acrylate and others such as perfluorocyclohexyl acrylate. In addition to the fluorochemical compound having an ethylenic unsaturation, comonomers such as acrylates and methacrylates can be used.
Suitable end-capping agents typically include a mercapto group and a functional group capable of reacting with an isocyanate. Such functional groups include hydroxy and amino. Examples of end-capping agents include 2-mercaptoethanol, 11-mercaptoundecanol, 3-mercapto-2-butanol, 1-mercapto-2-propanol, 2-mercaptopyridinol, o-, m-, and p-thiocresol and 2-mercaptoethylamine. Preferred functionalized end-capping agents include 2-mercaptoethanol, 4-mercaptobutanol and 2-mercaptoethylamine.
Suitable diisocyanates that can be used include aromatic diisocyanates such as 4,4xe2x80x2-methylenediphenylenediisocyanate, 4,6-di-(trifluoromethyl)-1,3-benzene diisocyanate, 2,4-toluenediisocyanate, 2,6-toluene diisocyanate, o, m, and p-xylylene diisocyanate, 4,4xe2x80x2-diisocyanatodiphenylether, 3,3xe2x80x2-dichloro-4,4xe2x80x2-diisocyanatodiphenylmethane, 4,5xe2x80x2-diphenyldiisocyanate, 4,4xe2x80x2-diisocyanatodibenzyl, 3,3xe2x80x2-dimethoxy-4,4xe2x80x2-diisocyanatodiphenyl, 3,3xe2x80x2-dimethyl-4,4xe2x80x2-diisocyanatodiphenyl, 2,2xe2x80x2-dichloro-5,5xe2x80x2-dimethoxy-4,4xe2x80x2-diisocyanato diphenyl, 1,3-diisocyanatobenzene, 1,2-naphthylene diisocyanate, 4-chloro-1,2-naphthylene diisocyanate, 1,3-naphthylene diisocyanate, and 1,8-dinitro-2,7-naphthylene diisocyanate; alicyclic diisocyanates such as 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate; 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate; aliphatic diisocyanates such as 1,6-hexamethylenediisocyanate, 2,2,4-trimethyl-1,6-hexamethylenediisocyanate, and 1,2-ethylenediisocyanate and cyclic diisocyanates such as isophorone diisocyanate (IPDI). Also, other diisocyanates such as those available from Bayer under the trademark DESMODUR(trademark) can be used, for example DESMODUR(trademark) TT and DESMODUR(trademark) W.
In a second reaction separate from the above reaction, a diisocyanate which may be the same or different as the one used in the above described reaction, is reacted with a monomer that contains a group capable of reacting with an isocyanate such as hydroxy or amino. Preferred monomers are acrylates, methacrylates, acrylamides and methacrylamides. Especially preferred monomers correspond to the following formula: 
wherein:
X3 and X4 are each independently selected from O or NH,
R1 is a linear or branched alkylene having 1 to 4 carbon atoms or a poly(oxyalkylene) containing group, and
R2 is hydrogen or a methyl group.
Specific examples include 2-hydroxyethyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 6-hydroxy-hexyl(meth)acrylate, mono (meth)acrylates of a polyethylene glycol, mono (meth)acrylates of a block copolymer of ethylene oxide and propylene oxide; mono (meth)acrylates of amino-or diamino- terminated polyethers and mono (meth)acrylates of tetramethylene oxide glycols.
The reaction products of the above described first and second reaction can then be combined and reacted with a compound of the formula HX1xe2x80x94B1xe2x80x94X2H. Suitable compounds of the latter formula are described herein. The reaction conditions that can be employed in each of these three reactions are the conventional reaction conditions employed in reacting an isocyanate. Preferably the reactions are run in the presence of a catalyst. Suitable catalysts include tin salts such as dibutyltin dilaurate, stannous octanoate, stannous oleate, tin dibutyldi-(2-ethyl hexanoate), stannous chloride; and others known to those skilled in the art. The amount of catalyst present will depend on the particular reaction, and thus it is not practical to recite particular preferred concentrations. Generally, however, suitable catalyst concentrations are from about 0.001 percent to 10 percent, preferably about 0.1 percent to 5 percent, by weight based on the total weight of the reactants.
The condensation reactions are preferably carried out under dry conditions in a polar solvent such as ethyl acetate, acetone, methyl isobutyl ketone, toluene and the like. Suitable reaction temperatures will be easily determined by those skilled in the art based on the particular reagents, solvents, and catalysts being used. While it is not practical to enumerate particular temperatures suitable for all situations, generally suitable temperatures are between about room temperature and about 120xc2x0 C.
Monomers according to formula (I) wherein s is 0 can be prepared in a single step by reacting the fluorochemical oligomer and a monomer that contains a group capable of reacting with an isocyanate such as hydroxy or amino with a diisocyanate. Suitable diisocyanates, monomers containing a group capable of reacting with an isocyanate and the fluorochemical oligomers are described herein.
As described herein, where the monomer according to formula (I) does not include a polyoxyalkylene group, the polymer is derived from a copolymerisation of a monomer according to formula (I) and a comonomer containing a poly(oxyalkylene) group. The comonomer containing a poly(oxyalkylene) group can be a monomer corresponding to formula (I) with s being 1 or L2 containing a poly(oxyalkylene) group, but preferably it is a monomer that does not contain a fluorochemical group. Preferred comonomers correspond to the following formula: 
wherein:
R6, R7 and R8 are each independently selected from the group consisting of linear or branched alkylenes having 2 to 4 carbon atoms;
R9 is hydrogen or an alkyl group having 1 to 4 carbon atoms;
x and y are each independently an integer of 0 to about 30, typically 0 to about 20 and preferably 0 to about 16, and the sum of x and y is at least about 5;
and R10 is hydrogen or a methyl group.
Examples of comonomers containing a poly(oxyalkylene) group include mono (meth)acrylates of a polyethylene glycol, mono (meth)acrylates of a block copolymer of ethylene oxide and propylene oxide; mono (meth)acrylates of amino- or diamino-terminated polyethers and (meth)acrylates of methoxypolyethyleneglycols.
The polymer of the fluorochemical composition is typically prepared by free radical polymerisation e.g. by solution- or emulsion polymerization techniques. The polymerisation can be a thermal or photochemical polymerisation. Useful free radical initiators are known in the art and include azo compounds, such as azo(bis)-isobutyronitrile and azo(bis)-2-cyanovaleric acid, hydroperoxides such as cumene, t-butyl and t-amyl hydroperoxide, dialkyl peroxides such as di-t-butyl and dicumylperoxide, peroxyesters such as t-butylperbenzoate and di-t-butylperoxy phtalate, diacylperoxides such as benzoyl peroxide and lauryl peroxide.
The fluorochemical composition is soluble in various organic solvents such as ethyl acetate, ethers (di-propylene glycol mono methyl ether, tetrahydrofuran, ethylene glycol ethers), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone), alcohols (methanol, ethanol, isopropyl alcohol, glycols), dimethylpyrrolidone and mixtures thereof Accordingly, the fluorochemical composition can be used as a solution in an organic solvent or alternatively, an emulsion of the fluorochemical composition in water can be prepared according to well-known techniques. For example, a solution of the fluorochemical composition in an organic solvent, e.g. ethylacetate, gradually can be added to a solution of an emulsifier in water with vigorous stirring. The thus obtained pre-mix may then be subjected to ultrasound treatment or high shear homogenization to obtain a milky to transparent emulsion of the fluorochemical composition in water. If desired, the organic solvent can then be removed e.g. by distillation under reduced pressure.
The fluorochemical composition of this invention can be applied using conventional application methods but is preferably used as an aqueous emulsion. Alternatively, it can be used as a treatment composition in solvent. An aqueous emulsion will generally contain water, an amount of fluorochemical composition effective to provide repellent properties to a substrate treated therewith, and a surfactant in an amount effective to stabilize the emulsion. Water is preferably present in an amount of about 70 to 2000 parts by weight based on 100 parts by weight of the fluorochemical composition of the invention. The surfactant is preferably present in an amount of about 1 to 25 parts by weight, preferably about 2 to 10 parts by weight, based on 100 parts by weight of the fluorochemical composition. Conventional cationic, nonionic, anionic, and zwitterionic surfactants are suitable.
The amount of the treating composition applied to a substrate in accordance with this invention is chosen to impart the desired stain release properties to the substrate surface. Typically, an amount of treating composition sufficient to provide about 0.01% to 5% by weight, preferably about 0.05% to 2% by weight, based on the weight of the substrate, of fluorochemical composition on the treated substrate is sufficient. The amount which is sufficient to impart desired stain release can be determined empirically and can be increased as necessary or desired.
To the fluorochemical composition of the invention there may also be added other fluorinated products, polymers or auxiliary products such as starch, dextrin, casein, polyvinyl alcohols, cellulose and cellulose derivatives such as cellulose ethers, copolymers of (meth)acrylic acid and alkyl esters of (meth)acrylic acid, polyglycols such polyethylene glycols, sizing agents, materials to improve water and/or oil repellency, fire proofing or antistatic properties, buffering agents, fungicidal agents, optical bleaching agents, sequestering agents, mineral salts, surface-active agents, or swelling agents to promote penetration.
Particularly suitable auxiliary products for use in the fluorochemical composition include polyvinyl alcohols, polyethylene glycols, non-ionic cellulose ethers and copolymers of an alkyl (meth)acrylate and (meth)acrylic acid. It was found that in many cases, these auxiliary products improve the stain release performance of the fluorochemical composition. Preferred polyvinyl alcohols are polyvinyl alcohols having a degree of hydrolysis of at least about 65% by weight and more preferably a degree of hydrolysis of at least about 80% by weight.
Examples of non-ionic cellulose ether derivatives include methyl cellulose, hydroxypropyl cellulose and methylhydroxypropyl cellulose. Particularly preferred cellulose ethers are hydroxyalkyl cellulose ethers. Preferably, the etherified cellulose is highly hydrophilic. Accordingly, cellulose ethers that contain large hydrophobic substituents, such as the hydrophobically modified cellulose ether available from Aqualon under the trademark NEXTON(trademark), are not preferred for use in the fluorochemical composition of this invention.
The polyethylene glycols useful as additives are preferably homopolymers of ethylene oxide and typically have a molecular weight between about 200 and 5000.
Preferred copolymers of an alkyl(meth)acrylate and (meth)acrylic acid are copolymers in which the weight ratio of (meth)acrylic acid to the alkyl(meth)acrylate is between about 20:80 and 90:10. More preferably, the weight ratio is between about 50:50 and 85:15. It is further preferred that the alkyl group of the (meth)acrylate monomer is a lower alkyl group having about 1 to 6 carbon atoms. Examples of alkyl (meth)acrylate monomers include, methyl, ethyl and n-butyl acrylates and methacrylates. The copolymer of an alkyl (meth)acrylate and (meth)acrylic acid may further contain moieties derived from ethylenically unsaturated monomers, but preferably, the copolymer only consists of moieties derived from alkyl (meth)acrylates and (meth)acrylic acid. The copolymer may also be partially or fully neutralised with a base such as sodium hydroxide or ammonium hydroxide.
The substrates treated with the fluorochemical composition of this invention are not especially limited and include plastic, metal, glass, fibrous materials such as textile fabrics, wood, non-wovens and paper. The fluorochemical composition is particularly useful for imparting stain release properties to a substrate that comprises natural fibers, in particular a substrate that consists of cellulose fibers or a substrate consisting of cellulose and polyester fibers. Substrates treated with a fluorochemical composition of this invention have particular good stain release properties for dirty motor oil stains and tea stains.
In order to affect treatment of a textile substrate, the substrate can be immersed in a diluted emulsion. The saturated substrate can then be run through a padder/roller to remove excess emulsion, dried and cured in an oven at a temperature and for a time sufficient to provide a cured treated substrate. This curing process is typically carried out at temperatures between about 50xc2x0 C. to 190xc2x0 C. depending on the particular system or application method used. In general, a temperature of about 120xc2x0 C. to 170xc2x0 C., preferably about 150xc2x0 C. to 170xc2x0 C. for a period of about 20 seconds to 10 minutes, preferably 3 to 5 minutes, is suitable. The cured treated substrate can be used as desired, e.g., incorporated or fashioned into a garment.